The conventional means for accommodating a wide range of conduit or cord diameters within an electrical device has been to use a removable or expandable conduit clamp. For example, a conduit clamp capable of accommodating a small diameter conduit can be removed when a larger diameter conduit is desired. The clamp reduces the opening size of the electrical device, thereby allowing the conduit clamp to effectively grip the smaller diameter conduit within the opening.
Such removable clamps have several disadvantages. The electrical devices are manufactured with the clamps installed and ready to receive a predetermined diameter conduit. A user has the option to order electrical devices having clamps capable of retaining conduits of a predetermined diameter. If the user procures electrical devices with clamps that can retain only smaller diameter conduits than required, the user can remove the clamps in order to accommodate a larger conduit. However, if the user does not remove the clamps, and attempts to insert the larger conduit, the conduit can be damaged. Additionally, if the user removes the clamps, there will be no retaining mechanism remaining within the electrical device.
Permanent adjustable clamps have also been utilized, however they require both rotary and translational movement to be effective and are usually complicated and costly to make and assemble. See, for example, U.S. Pat. No. 5,217,389 to MacKay et al and U.S. Pat. No. 5,562,483 to Hoffman.
Thus, a need exists to provide an electrical device with a clamp capable of retaining various sizes of conduit, whereby a user can alter the clamp to retain larger diameter conduit.